CN1044467A - L-aspartyl-L-Ala, Serine and glycine dipeptide ester and acid amides sweeting agent simple substance or mixture and preparation method - Google Patents

Abstract

L-aspartyl-L-Ala, Serine and glycine dipeptide ester and acid amides sweeting agent simple substance or mixture and preparation method, the D-that can utilize fully with human body or DL-L-Ala, D or DL-serine, glycine, L-Aspartic Acid are made raw material, adopt the whole bag of tricks of synthetic peptide to obtain, it is compared with edible at present dipeptide sweetener aspartame has the stability height, nontoxicity, production cost are low, its sugariness is 400 times of sucrose to more than 2600 times five kinds after measured, and different local flavors is arranged.Its diastereomer does not all have bitter taste.

Description

L-aspartyl-L-Ala, Serine and glycine dipeptide ester and acid amides sweeting agent simple substance or mixture and preparation method

The invention belongs to the chemosynthesis dipeptide sweetener.

Mazur[(R.H.Mazur in 1969, J.Amer.Chem.Soc., 91,2684(1969)] and found the novel flavor agent of a class, general expression is:

It is a benzyl for R, the hygiene department that is present many countries permits edible sweeting agent, trade name aspartame (Aspartame, be abbreviated as APM), its sugariness is 200 times of sucrose, though APM is widely used, it remains in weak point: 1. the phenylalanine in its structure, Propiophenone uremic patient to congenital hereditary has severe toxicity, and the baby is inedibility more.2. the methyl esters in the structure is all unstable to acid, alkali, heat, usually should in the low temperature food product of pH3-5, use, as in moisture food, put for a long time and will become diketopiperazine or be hydrolyzed into acid, its degradation production has bitter taste, and the time limit all is subjected to temperature so the food that contains this sweeting agent in accumulating, goes on the market, the environmental influence of humidity and the restriction of half life of decomposition own have inconvenience during use.

Fujino[M.Fujino et al. in 1973, (a) Naturwiss., 60,351, (1973); (b) Chem.Pharm.Bull., 24,2112(1976)] reported a dipeptide sweetener with 22000-33000 times of sugariness, i.e. L-aspartyl-amidomalonic acid first turnip dibasic acid esters, its structural formula is:

Fenchol has four kinds of steric isomers, promptly d-α-, d-β-, 1-α-, 1-β-fenchol, wherein the dipeptides sugariness of d β-fenchol is the highest, but its structure, include non-natural synthetic ingredient, because it comprises methoxycarbonyl and turnip ester group, its unstable degree goes even farther than AMP.

It is low that the object of the invention is to seek out a kind of toxicity, sugariness height, good stability, the dipeptide sweetener that price is honest and clean, we design the amino acid that adopts nature to exist fully for this reason, and with Aspartic Acid, L-Ala, Serine and glycine synthesize dipeptide sweetener.

The present invention is characterized as such L-asparaginyl aminodipeptide ester or acid amides, and general expression is:

R in the formula ₂Be respectively CH ₃, CH ₂OH, H; R ₁Can be OR or NHR:

The following method that synthetic this compounds adopts usually:

A. amino acid is through carbobenzoxy chloride or carbobenzoxy chloride, and contraposition has the carbobenzoxy chloride of replacement, acids, formic acid formylation protection ammonia terminal amino acid; Alcohols or trimethylchlorosilane protection carboxylic terminal amino acid.

B. the amino acid of two kinds of protections is through dicyclohexylcarbodiimide (DCCI), mixed acid anhydride, and condensation gets dipeptide compound.

C. the peptide compounds that contains protecting group is sloughed protecting group through palladium black hydrogenolysis, Hydrogen bromide hydrolysis.

Adopt the amino acid whose ammonia end of aforesaid method A and carbobenzoxy chloride or carbobenzoxy chloride, carbobenzoxy chloride, acids that contraposition has replacement react at equal solvents such as anhydrous diethyl ether, water, formic acid, tetrahydrofuran (THF), methylene dichloride, chloroform, ethyl acetate.Amino acid is L-Aspartic Acid, D-or D, L-L-Ala, D-or DL-serine, glycine.The L-Aspartic Acid is equipped with the synthetic a series of dipeptide sweeteners of glycine, L-Ala or Serine.The L-Aspartic Acid is in alkaline medium, and cooling adds carbobenzoxy chloride and sodium hydroxide down, after reaction is finished; wash with ether, remove unnecessary carbobenzoxy chloride, acidified aqueous solution; crystallization is separated out in cooling, gets N-carbobenzoxy-L-Aspartic Acid, and it and benzylalcohol are in the toluene solution that contains right-toluenesulphonic acids; the reacting by heating dehydration; add the magnesium oxide jolting after the cooling, filter removal of solvent under reduced pressure and excessive benzyl ester; get oily matter, recrystallization gets amino L-Aspartic Acid dibasic acid esters by the carbobenzoxy protection.Gained amino is dissolved in aqueous acetone by the L-Aspartic Acid dibasic acid esters of carbobenzoxy protection, and room temperature, stirring add the aqueous solution of lithium hydroxide down, boil off ketone under the low temperature; use extracted with diethyl ether, remove unreacted dibasic acid esters, water layer 6N hcl acidifying; get the β-benzyl ester of oily matter, recrystallization in the benzene.(embodiment 1).

Benzylalcohol under agitation joins in the ether sulfuric, removes ether, adds the L-Aspartic Acid, makes its whole dissolvings, placed one day, and stirred adding 95% ethanol down, cooling drips pyridine down while stirring, crystallization is separated out in placement, filters drying, gained L-Aspartic Acid-β-single benzyl ester.(embodiment 2)

L-Aspartic Acid β-single benzyl ester is dissolved in the hot water, make dissolving after, wait to be as cold as 60 ℃, add NaHCO ₃And carbobenzoxy chloride, continued stirring reaction 3 hours, shake with ether and give a baby a bath on the third day after its birth time, be acidified to pH2 with concentrated hydrochloric acid then, refrigerator is placed, and crystallization folds, and filters, dry, recrystallization gets the L-Aspartic Acid β-benzyl ester of ammonia end by the carbobenzoxy-(Cbz) protection.(example 3) amido protecting of L-Aspartic Acid and the priority of carboxy protective, but the particular case of visual response and deciding.

The L-Aspartic Acid is made the acid anhydrides hydrochloride.The L-Aspartic Acid stirs into floating suspension in tetrahydrofuran (THF), add phosphorus oxychloride (POCl ₃) or phosphorus trichloride (PCl ₃), stirring reaction is cooled to 5-10 ℃ and continues reaction, after reacting completely, filters, and crystallization is washed with tetrahydrofuran (THF), gets the acid anhydrides hydrochloride of L-Aspartic Acid.(example 4).

L-Aspartic Acid ammonia end is by formic acid formylation protection, and simultaneously, the α carboxyl makes it be dehydrated into acid anhydrides.Gradually splash into aceticanhydride in 95% formic acid, once add the L-Aspartic Acid then, stir after 2 hours, placement is spent the night.Extract excessive formic acid and aceticanhydride next day, gets N-formyl radical L-Aspartic Acid acid anhydride white solid (embodiment 5).After carbobenzoxy-L-Aspartic Acid and the aceticanhydride reaction, promptly get acid anhydrides (example 6).

Above-mentioned method, energy synthetic ammonia end is by the D-or the D of carbobenzoxy chloride protection, L-L-Ala, D-or D equally; the L-Serine, glycine, they are in alkaline medium; under the cooling and stirring, splash into carbobenzoxy chloride in batches, and alternately splash into 4N NaOH; make solution keep weakly alkaline all the time, after finishing, 0 ℃ of reaction down; reaction is washed with ether, to remove unnecessary carbobenzoxy chloride after finishing; reaction solution is used ethyl acetate extraction with 6N HCl acidifying, gets crystallization.(example 7).

Amino acid whose carboxylic end is handled by alcohol or amine, makes different esters or acid amides respectively.With by L-Ala, fenchol and the Phenylsulfonic acid of carbobenzoxy protection in benzene or benzene-toluene mixed solvent, reacting by heating after reaction finishes, is used NaHCO ₃The aqueous solution and be washed to neutrality, drying is removed and is desolvated, oily matter be the amino L-Ala turnip ester of protecting by carbobenzoxy; again at room temperature with palladium black, in the methanol solution, logical hydrogen, treat that hydrogenolysis is finished after; the elimination palladium black is removed and is desolvated, and the layer of silica gel folding gets D-L-Ala-L-α-turnip ester (example 8).

In the presence of right-toluenesulphonic acids, with the L-Ala and 2 of carbobenzoxy protection, the 6-dimethyl cyclohexanol reacts in benzene, react finish after, treat to use NaHCO after cold ₃Be washed to neutrality, the extraction solution anhydrous Na ₂SO ₄Drying, remove desolvate oily matter, again oily matter is dissolved in the methyl alcohol, in the presence of catalyzer-palladium black, room temperature lead to hydrogen, elimination palladium black, except that desolvating, must D-L-Ala-2,6-dimethyl cyclohexyl (example 9).

The L-Ala of carbobenzoxy protection is dissolved in the anhydrous diethyl ether, and cooling stirring down adds equimolar phosphorus pentachloride, treats CL, adds equimolar neighbour-Tolylamine, and in the presence of triethylamine, low-temp reaction after question response finishes, filters, and the filtrate washing is to neutrality, Na ₂SO ₄Drying, the pressure reducing and steaming solvent gets the L-Ala acyl-neighbour-Tolylamine of carbobenzoxy protection, at excessive Hydrogen bromide; glacial acetic acid solution exists down, room temperature treatment, and concentrating under reduced pressure is to certain volume; with vinyl acetic monomer dilution, place white crystals, alanyl-neighbour-Tolylamine hydrogen bromide salt (example 10).

Equally, the L-Ala of carbobenzoxy protection, in chloroform, stirring, cooling add the reaction of isobutyl chlorocarbonate and N-methylmorpholine down, add 2 again, 6-xylidine, stirring reaction, reaction solution 0.5N HCl and NaHCO ₃Solution washing, distilled water is washed till neutrality, and drying is removed and is desolvated, and getting solid is N-carbobenzoxy-L-Ala-2,6-xylyl acid amides, recrystallization purifying is used palladium black hydrogenation under normal pressure, normal temperature again, promptly gets L-Ala-2,6-xylyl acid amides (example 11).Carboxylic terminal amino acid and protecting group reaction solvent have vinyl acetic monomer, dimethyl formamide, ethanol, chloroform, methylene dichloride, dioxane.

Adopt the L-Ala of aforesaid method B carbobenzoxy protection to make solvent at pyridine, the Phenylsulfonic acid of catalytic amount exists down, adds excessive ortho-xylene phenol; add carbodicyclo hexylimide in batches, stir, solid is separated out; placement is spent the night; the elimination solid, filtrate water dilution, 6N HCl acidifying; the elimination solid; filtrate is with ethyl acetate extraction, and the above-mentioned solid that leaches is dissolved in vinyl acetic monomer, washing, saturated NaHCO ₃Wash, wash, most of solvent is removed in washing successively, adds an amount of sherwood oil, places and separates out solid, gets the L-Ala-2 of carbobenzoxy protection, and 6-diformazan phenyl ester after the palladium black catalytic hydrogenation, gets D-or D, L-L-Ala-2,6-diformazan phenyl ester.(example 12).

With D-L-Ala-2; 6-dimethyl cyclohexyl is dissolved in methylene dichloride, adds carbobenzoxy-L-β-Aspartic Acid benzyl ester, adds dicyclohexylcarbodiimide and methylene dichloride; room temperature reaction spends the night; filter, remove methylene dichloride and get oily matter, this shape thing is dissolved in methyl alcohol; add the palladium black hydrogenolysis; remove protecting group, purified L-α-aspartyl-D-L-Ala-2, the 6-diformazan cyclohexyl (example 13) of getting.For practicality, we also make corresponding D, L-L-Ala product.

Adopt aforesaid method C by N-carbobenzoxy-glycine-D-β-turnip ester, D-carbobenzoxy L-Ala-L-α-turnip ester, D-carbobenzoxy-L-Ala-D-β-turnip ester gets glycine-D-β-turnip ester, D-L-Ala-L-α-turnip ester and D-L-Ala-D-β-turnip ester respectively through the palladium black hydrogenolysis.Then respectively with CBZ-L-β-Aspartic Acid benzyl ester, make solvent at methylene dichloride, add carbodicyclo hexylimide, room temperature reaction, reaction finishes, and filters, and removes and decrystallizes organic phase NaHCO ₃, HCl and washing, dry, remove desolvate oily matter, this oily matter is dissolved in methyl alcohol, adds palladium black and carries out hydrogenolysis, after reaction finishes, filter, remove catalyzer and solvent, oily matter is through the silica gel column chromatography purifying, get L-α-aspartyl-glycine-D-β-turnip ester (example 14), L-α-aspartyl-D-L-Ala-L-α-turnip ester (example 15) and L-α-aspartyl-D-L-Ala-D-β-turnip ester (example 16) respectively.For practicality, we have also prepared corresponding D, L-L-Ala product.

L-α-aspartyl-D-the alanyl 2 of same CBZ protection; 6-xylidene(s) acid amides can be by carbobenzoxy-L-β-Aspartic Acid benzyl ester and N-methylmorpholine in chloroform; cooling adds isobutyl chlorocarbonate down; after the reaction, add D-L-Ala-2 again, 6-xylyl acid amides; N-methylmorpholine is in chloroformic solution; stirred overnight at room temperature, HCl acidifying, NaHCO ₃Wash, wash to neutrality anhydrous Na with water ₂SO ₄Drying is filtered, and removal of solvent under reduced pressure gets solid, and this solid is put into the hydrogenation bottle, add the first alcohol and water, add palladium black, room temperature, normal pressure hydrogenation a few hours, clear solution, the elimination palladium black is drained solvent, gets L-α-aspartyl-D-alanyl-2,6-xylidene(s) acyl.(example 17).For practicality, we have also prepared corresponding D, the non-enantiomer mixture of L-L-Ala.Other solvents of catalytic hydrogenolysis have ethanol, dioxane, tetrahydrofuran (THF), acetic acid, Virahol, propyl carbinol.

Now, be expressed as follows (videing infra) with chemical equation with the four-step reaction of above-mentioned three main routes:

The present invention designs the food amino acid that a class adopts nature to exist fully, and for example L-Aspartic Acid, L-Ala, Serine glycine are made raw material, synthetic dipeptide sweetener.

D-L-Ala (being the beans composition) can transform and complete digestion for human body 100%, glycine exists in human body equally, participate in tricarboxylic acid cycle indirectly, inexpensive, fenchol (fennel composition) is more than methyl alcohol safety, by fenchol synthetic dipeptides ester, fine to thermostability, can reflux in water (＞100 ℃) 12 hours are still pleasantly sweet.Synthetic one class dipeptide sweetener of the present invention is L-aspartyl-D-L-Ala-2 after measured, and 6-xylidene(s) acid amides sugariness is 500 times of sucrose, L-aspartyl-Gan

Propylhomoserin-D-β-turnip ester sugariness is 600 times of sucrose, and L-aspartyl-D-L-Ala-L-α-turnip ester sugariness is 600 times of sucrose, and L-door winter ammonia-D-L-Ala-D-β-turnip ester sugariness is 2400-2600 a times of sucrose.Therefore, adopt synthetic dipeptides method of the present invention,,, and have various local flavor and than high chemical stability and antimicrobial decomposition so synthetic dipeptide sweetener cost can be lower than AFM because raw material is cheap amino acid.

Example 1:

The preparation of N-CBZ-L-Aspartic Acid-β-benzyl ester

L-Aspartic Acid 10.31g(77 millimole) is dissolved in 50 milliliters of 4N NaOH, under stirring at room, drips 15 milliliters of toluene solutions of carbobenzoxy chloride (CBZCl) 17 milliliters (95 millimoles), after dripping off, continue to stir 3 hours, keep about pH13.After the phase-splitting, water is washed once with toluene, is acidified to pH1-2 with 6N HCl then, uses ethyl acetate extraction again, vinyl acetic monomer solution anhydrous Na ₂SO ₄Drying, removal of solvent under reduced pressure, a jelly, add small amount of toluene after, put into refrigerator, separate out white solid, filter washing, dry 18 grams, productive rate 87%, fusing point 104-107 ℃.The carbobenzoxy of aforesaid method gained protection L-Aspartic Acid 9 grams and 40 milliliters of addings of benzylalcohol are contained in the solution of 50 milliliters of toluene that a toluenesulphonic acids 0.5 is restrained and reflux; the spinner azeotropic is housed to anhydrate; 2.5 hour anhydrate 2.5 milliliters approximately; the cooling back adds magnesium oxide 1 gram jolting 10 minutes; filter; pressure reducing and steaming toluene and superfluous benzylalcohol; get oily matter; use the sherwood oil recrystallization; get m.p.58 ℃ of white N-CBZ-L-Aspartic Acid dibenzyl ester 11 gram; again with boiling the sherwood oil recrystallization once, m.p.66.5 ℃ of gained white crystals, [α] ²⁵ _D-25 ° (C=10, HOAc).

L-Aspartic Acid dibasic acid esters 4.5 grams of the CBZ of above-mentioned gained protection are dissolved in 250 milliliters of aqueous acetone (water: acetone is 1:4), in room temperature, in 0.5 hour; stirring adds 10 ml water solution of lithium hydroxide 0.255 gram, boiling off acetone below 40, removes unreacted dibasic acid esters with extracted with diethyl ether; water layer 6N HCl acidifying; getting oily matter is N-CBZ-L-Aspartic Acid-β-benzyl ester, places crystallization and separates out, and gets 2.5 grams; productive rate 70%; the benzene recrystallization, m.p.107-109 ℃, [α] ²⁵ _D+ 13.1 ° (C=10HOAc).

Example 2:

The preparation of L-Aspartic Acid-β-single benzyl ester

20 milliliters of the vitriol oils splash in 200 milliliters of the anhydrous diethyl ethers that stir, add 200 milliliters of benzylalcohols again, the pressure reducing and steaming ether changes in 1000 milliliters of three-necked bottles again, under agitation adds L-Aspartic Acid 26.8 grams till whole dissolvings, room temperature was placed one day, under agitation add 400 milliliters of 95% ethanol, in ice bath, stir 100 milliliters of adding pyridines, cooling is placed and is spent the night, and has precipitation to separate out.Filter, add diethyl ether and grind throw out, refilter, with the water recrystallization secondary that contains several pyridines, 16.2 gram L-Aspartic Acid β-benzyl esters.m.p.220-222℃。

Example 3:

The preparation of N-CBZ-L-Aspartic Acid-β-benzyl ester:

L-Aspartic Acid-β-benzyl ester 8.9 grams (40 millimole) that make in the example 2 are put in the three-necked bottle, and adorned agitator, dropping funnel and thermometer, add 600 milliliters of hot water, stir, content is all dissolved, be cooled to 60 ℃ (58 ℃ time will have solid to separate out) then, add NaHCO ₃7 gram (100 millimole) and carbobenzoxy chloride (CBZCl) 48 millimoles, are kept 60 ℃ and were stirred 1.5 hours by 12 milliliters.Shake give a baby a bath on the third day after its birth time (3X100ml) with ether, be acidified to pH2 with dense HCl then, put refrigerator overnight, must solid, behind the filtration drying again recrystallization get N-carbobenzoxy-L-β-Aspartic Acid benzyl ester 10g, m.p.107-109 ℃, [α] ²⁵ _D+ 13.1 ° (C=10, HOAc)

Example 4:

The preparation of L-Aspartic Acid acid anhydride hydrochloride

Mid-50 milliliter of four furans of reaction flask and 5 gram (0.038 mol) L-Aspartic Acids splash into 4 milliliters of Phosphorus Oxychlorides under stirring, after dripping off, and stirring at room 5 hours, filter, and wash with tetrahydrofuran (THF), filter cake is put into moisture eliminator, after the drying, get white solid 2.9 grams, productive rate 50%, m.p.139-140 ℃.

If replace Phosphorus Oxychloride, almost can get quantitative yield, but its particle is thin, suction filtration difficulty, and the easy moisture absorption with phosphorus trichloride.

Example 5:

The preparation of formyl radical-L-Aspartic Acid acid anhydride

In 50 milliliters of reaction flasks; 95% formic acid that adds 1.2 milliliters, cooling adds 0.6 milliliter of aceticanhydride down gradually, under the stirring at room; once add 140 milligrams of L-Aspartic Acids; the solid dissolving continues to stir 2 hours, and placement is spent the night; excessive formic acid of pressure reducing and steaming and aceticanhydride in the hot water bath; promptly get white solid, gained N-formyl radical L-Aspartic Acid acid anhydride can be used the vinyl acetic monomer crystallization purifying, also can be directly used in and connect reactive polypeptide.

Example 6:

The preparation of N-carbobenzoxy-L-Aspartic Acid acid anhydride:

N-carbobenzoxy-L-Aspartic Acid 5 grams (18.7 millimole) and new 7 milliliters of the aceticanhydrides that steam, be heated to the dissolving of 40C solid, 30C kept 2 hours, boil off acetic acid and aceticanhydride, add ether, be warmed to dissolving, add a small amount of sherwood oil and make and separate out crystallization, get white needles body 3.46 grams (productive rate 65%), m.p.126-128 ℃.

Example 7:

The preparation of N-carbobenzoxy-D-L-Ala

In the reaction flask that stirring and dropping funnel are housed, add 28 milliliters of 4N NaOH, be cooled to-5 ℃, add 10 gram (0.11 mol) D-L-Ala then, stir down, two funnel wheel drips add 33 milliliters of (0.132 mol) 4N NaOH and 22 milliliters of (0.132 mol) chloroformic acid benzyl esters, keep the reaction solution slight alkalinity therebetween, dripped off in about 0.5 hour, and continued reaction 2 hours, then with the unreacted chloroformic acid benzyl ester of ether extraction, the water-bath cooling down, be acidified to pH2 with 5N HCl, use ethyl acetate extraction, anhydrous Na again ₂SO ₄Drying is filtered, and behind the pressure reducing and steaming solvent, gets white solid.The gained solid gets 19.24 grams, productive rate 78.4% m.p.82-83 ℃ [α] with ether-sherwood oil (30=60C) recrystallization ³⁹ _D+ 10 ° (C=1, HOAc).For practicality, we have also prepared D, the mixture of the corresponding diastereomer of L-L-Ala.

Ultimate analysis:

Theoretical value (C ₁₁H ₁₂NO ₄) C, 59.19 H, 5.83 N, 6.28

Experimental value C, 59.19 H, 5.89 N, 6.10

NMR(CDCl ₃Mark in the solvent TMS)

10.8（1H，s，-COOH）;7.2-7.33（5H，t，

）;

5.64（1H，m，-NH）;5.2（2H，s，-CH ₂-）;4.36

（1H，q，CH）;1.4（3H，d，CH ₂）.

Example 8:

The preparation of D-L-Ala-L-α-turnip ester

In the reaction flask that water trap and reflux condensing tube (connecing calcium chloride tube) is housed, the 910 milligrams of carbobenzoxys-D-L-Ala of packing into, 1.08 gram L-α-fenchols, 30 milliliters of benzene and 100 milligrams of tosic acid (TsOH H ₂O), reflux 20-24 hour, then use NaHCO ₃Solution and be washed to neutrality, anhydrous Na ₂SO ₄After the drying, remove desolvate 1.5 gram oily matter, with 30 ml methanol above-mentioned oily matter is dissolved, add 80 milligrams of palladium blacks, logical hydrogen 2-3 hour of room temperature, elimination palladium black, after the removal of solvent under reduced pressure, get D-L-Ala-L-α-turnip ester with silica gel column chromatography (sherwood oil and vinyl acetic monomer drip washing).

Ultimate analysis: theoretical value: N, 6.25 C, 68.67 H, 10.49

Experimental value: N, 6.22 C, 69.33 H, 10.22

Example 9:

D-L-Ala-2, the preparation of 6-dimethyl cyclohexyl

In reaction flask, add 2.25 gram (0.01 mol) CBZ-D-L-Ala, 2.06 gram (0.016 mol) 2,6-dimethyl cyclohexanol and 0.16 gram (0.00086 mol) are right-toluenesulphonic acids, add 45 milliliters of benzene, load onto water trap and prolong, refluxed 15 hours, use NaHCO after cold ₃Solution and be washed to neutrality, benzole soln water Na ₂SO ₄Drying after the removal of solvent under reduced pressure, gets 3.3 gram oily matter.

Above-mentioned oily matter is dissolved in the methyl alcohol, adds palladium black, room temperature hydrogenation 2 hours, the elimination palladium black, after the removal of solvent under reduced pressure, silica gel column chromatography (sherwood oil and vinyl acetic monomer drip washing) gets the pale yellow liquid of 1.46 grams, yield 73.4%.

Ultimate analysis: theoretical value: C, 66.33 H, 10.55 N, 7.04

Experimental value: C, 66.18 H, 10.85 N, 7.39

Example 10:

The preparation of alanyl-neighbour-Tolylamine hydrogen bromide salt

N-carbobenzoxy-L-Ala is dissolved in the anhydrous diethyl ether,, stirs the equimolar PCl of adding down at-5 ℃ ₅, treat complete molten after, add equimolar neighbour-toluene and the excessive slightly pre-cold soln of triethylamine anhydrous diethyl ether, the adularescent precipitation produces immediately, remains on-5 ℃ and stirs 3 hours, filter, with the vinyl acetic monomer washing, the filtrate difference water of merging, NaHCO ₃Solution and water washing are to neutral, through anhydrous Na ₂SO ₄After the drying, the pressure reducing and steaming solvent gets white solid, uses the vinyl acetic monomer recrystallization, and this is still the product of carbobenzoxy protection.After the solid of recrystallization at room temperature handled 2 hours with excessive HBr glacial acetic acid solution, a concentrating under reduced pressure part with the vinyl acetic monomer dilution, was placed the back and is obtained white crystals then, is alanyl-neighbour-Tolylamine hydrogen bromide salt.

Example 11:

D-alanyl-2, the preparation of 6-xylidene(s) acid amides

In reaction flask, add 4.46 gram (0.02 mol) carbobenzoxy D-L-Ala and add 50 milliliters of chloroforms, stir, cool off, the N-methylmorpholine that adds 2.75 milliliters of new distillatory isobutyl chlorocarbonates (0.02 mol) and 2.02 grams (0.02 mol), reacted 20 minutes, add 2.47 milliliters (0.02 mol) 2, the 6-xylidine, remove ice-water bath then, rise to room temperature, stirring is spent the night, reaction solution 0.5N HCl and NaHCO ₃Solution washing, distilled water is washed till neutrality, uses anhydrous Na ₂SO ₄Drying, after the filtration, removal of solvent under reduced pressure gets white solid, uses the vinyl acetic monomer recrystallization, gets 4.93 gram (75.6%) N-CBZ-L-Ala-2,6-xylyl acid amides.M.p.168-172 ℃, [α] ²⁷ _D+ 57.55 ° (C=1.02, ethanol).

Ultimate analysis: (C ₁₉H ₂₂N ₂O ₃) theoretical value: C, 69.64 H, 6.75 N, 8.59

Experimental value: 69.28 6.69 8.51

Mark in the NMR(chloroform solvent TMS)

1.50（3H，d，CH ₃），2.15（6H，s，

），4.46（1H，m，CH），

5.12（2H，s，CH ₂Ph），5.52（1H，d，-CO-NH-），7.58（1H，s，

）

7.06（3H，m，

），7.35（5H，s， ）。

Above-mentioned product 4.1 grams (0.0126 mol) are dissolved in the methanol solution that 60 ml methanol and 20 milliliters contain 15.7%HCl, add 0.4 gram palladium black, atmospheric pressure at room hydrogenation 6 hours, after the hydrogenation, promptly filter, remove and desolvate, get 2.83 gram white solid D-alanyls-2,6-xylidene(s) acid amides, productive rate 98.5%.For practicality, we have also prepared D, the respective mixtures product of L-L-Ala.

M.p.262-264 ℃, [α] ²² _D+ 45.03 ° (C=1.31, ethanol).

Ultimate analysis: theoretical value: C, 57.76 H, 7.49 N, 12.25 Cl, 15.5

Experimental value: 57.71 7.52 12.33 14.37

Example 12:

L-Ala-2, the preparation of 6-diformazan phenyl ester

Add 1.68 gram N-CBZ-L-Ala in reaction flask, the Phenylsulfonic acid of the o-Xylol phenol of 1.92 grams and 0.4 gram is with 20 milliliters of pyridine dissolvings, add dicyclohexylcarbodiimide 1.86 grams in batches, soon solid is separated out, and placement is spent the night, elimination next day solid, the filtrate water dilution, 6N HCl acidifying leaches solid, and filtrate is with ethyl acetate extraction, dissolve in solution with water, saturated NaHCO with above-mentioned solid product merging ₃After washing successively with water, with anhydrous Na ₂SO ₄Drying boils off most of solvent, adds an amount of sherwood oil, and solid is analysed, and filters, and after the drying, promptly gets N-CBZ-L-Ala-2,6-diformazan phenyl ester 1.4 grams.

To go up gained N-carbobenzoxy-L-Ala-2,6-diformazan phenyl ester is dissolved in the methyl alcohol, and in palladium black catalysis, methyl alcohol is removed in normal pressure and temperature hydrogenation 2 hours after the filtration, carry out column chromatography, promptly gets L-Ala-2,6-diformazan phenyl ester.For practicality, we have also prepared D, the mixture of the corresponding diastereomer of L-L-Ala.

Ultimate analysis: C ₁₁H ₁₅NO ₂

Theoretical value: C, 68.39 H, 7.77 N, 7.25

Experimental value: 68.12 7.98 6.68

Example 13:

L-α-aspartyl-D-L-Ala-2, the preparation of 6-one diformazan cyclohexyl

1.16 gram D-L-Ala-2,6-one dimethyl cyclohexyl is dissolved in 30 milliliters of methylene dichloride, adds 2.1 gram N-CBZ-L-β-Aspartic Acid benzyl esters, add 1.22 gram two hexamethylene carbodiimides and 20 milliliters of methylene dichloride, room temperature is let slip night, filters, after methylene dichloride is removed in decompression, get 3.34 gram soup compounies.

Get above-mentioned soup compound 2 grams and be dissolved in 40 ml methanol, add 200 milligrams of palladium blacks, hydrogenation is 3 hours under the room temperature, the elimination palladium black, decompression is removed methyl alcohol and is got 1.3 gram crude products, and this crude product with silicon column chromatography (vinyl acetic monomer and methyl alcohol drip washing), is got white powder 1 gram, productive rate 91% m.p.103-105 ℃, sugariness is 400 times of sucrose.[α] ¹⁰ _D47°，C＝1.0，HOAc/H ₂O＝1/1。For practicality, we have also prepared D, the mixture of the corresponding diastereomer of L-L-Ala.

Ultimate analysis:

Theoretical value: C, 54.38 H, 8.76

Experimental value: 54.47 7.87

Example 14:

The preparation of L-α-aspartyl-glycine-D-β-turnip ester

1.24 gram glycine-D-β-turnip ester, N-carbobenzoxy-L-β-Aspartic Acid benzyl ester 2.07 grams (5.90 millimole) are dissolved in 40 milliliters of methylene dichloride, add 1.5 gram (5.90 millimole) dicyclohexylcarbodiimide, room temperature, stirring 5 hours, filter organic phase NaHCO ₃, anhydrous Na is used in HCl and water washing then ₂SO ₄Drying, removal of solvent under reduced pressure gets syrup thing 3.31 grams.

Getting above-mentioned crude product 3.02 grams is dissolved in 40 ml methanol, add 250 milligrams of palladium blacks, hydrogenation 3 hours, the elimination palladium black, methyl alcohol is removed in decompression, the thick product of 1.93 grams, get wherein 0.895 gram through silica gel column chromatography (with vinyl acetic monomer and methyl alcohol drip washing) 0.47 gram (82.1%) m.p.125-126 ℃, [α] ²⁶ _D-15.5 °, C=2.8, HOAc/H ₂O=1/1, mass spectra peak: 327(M+1), 173,137(100%), 81.Sugariness 600X sucrose.

Example 15:

The preparation of L-α-aspartyl-D-L-Ala-L-α-turnip ester

In the dichloromethane solution of 270 milligrams of D-L-Ala-L-α-turnip esters, add 500 milligrams of N-CBZ-L-β-Aspartic Acid benzyl ester, add 350 milligrams of dicyclohexylcarbodiimide, reaction is 15 hours under the room temperature, elimination urea element then, and removal of solvent under reduced pressure gets 1 gram oily matter.

Above-mentioned gained oily matter is dissolved in 35 ml methanol, adds 65 milligrams of palladium blacks, the logical H-H reaction of room temperature 3 hours, filter, after the removal of solvent under reduced pressure, get L-α-aspartyl-D-L-Ala-L-α-turnip ester with silica gel column chromatography (vinyl acetic monomer-methyl alcohol drip washing), productive rate 70%, m.p.109-111 ℃, [α] ¹³ _D+ 13.8 °, sugariness is 1,000 times of sucrose.For practicality, we have also prepared corresponding D, the mixture of the diastereomer of L-L-Ala, about 500 times of sugariness.

Ultimate analysis: C ₁₇H ₂₀N ₂O _{5 '}H ₂O/ ₂

Theoretical value: C, 58.45 H, 8.30 N, 8.02

Experimental value: 57.53 8.23 8.00

Example 16:

The preparation of L-α-aspartyl-D-L-Ala-D-β-turnip ester

With etc. the N-CBZ-L-Aspartic Acid benzyl ester and the D-L-Ala-D-β-turnip ester of gram molecular weight be dissolved in the methylene dichloride, add the dicyclohexylcarbodiimide that is dissolved in methylene dichloride (with mol such as L-Ala turnip ester) then, very fast adularescent precipitation is separated out, placement is spent the night, the elimination solid, removal of solvent under reduced pressure adds methyl alcohol and palladium black, carry out hydrogenolysis, filter and remove methyl alcohol then, product separates with silica gel column chromatography, productive rate 64%, m.p.134-136 ℃, [α] ⁹ _D+ 24.10 ° of HOAc/H ₂O=1/1, C=0.1, sugariness is 2,600 times of sucrose.For practicality, we have also prepared D, L-L-Ala corresponding non-to shape allosome mix product, about 1,300 times of sugariness.

Ultimate analysis: C ₁₇H ₂₈N ₂O ₅H ₂O/2

Theoretical value: C, 55.58 H, 8.44 N, 7.63

Experimental value: C, 54.13 H, 7.94 N, 7.56

Example 17:

L-α-aspartyl-D-alanyl-2, the preparation of 6-xylidene(s) acid amides

In the reaction flask, be weighed into N-carbobenzoxy-L-β-Aspartic Acid benzyl ester 3.57 grams (0.01 mol), N-methylmorpholine 1.01 grams (0.01 mol) are in 50 milliliters of chloroforms, be chilled to-5C, add 1.38 milliliters of (0.01 mol) isobutyl chlorocarbonates, react after 45 minutes, add 2.29 gram (0.01 mol) D-alanyls-2, the 6-dimethylaniline dihydrochloride, 1.01 gram (0.01 mol) N-methylmorpholines are in the solution of 30 milliliters of chloroforms, and room temperature, stirring are spent the night.

With 0.5N HCl NaHCO ₃Wash, wash to neutrality anhydrous Na with water ₂SO ₄Drying is filtered, and removal of solvent under reduced pressure gets white solid, washes with vinyl acetic monomer, and drying gets product 4.49 grams (84.5%), and m.p.202 ℃, [α] ²² _D+ 40 ° (C=1, chloroforms) for practicality, we have also prepared D, the mix product of the corresponding diastereomer of L-L-Ala.

Ultimate analysis: C ₃₆H ₃₃O ₄N ₂H ₂O/2).

Theoretical value: C, 66.65 H, 6.34 N, 7.77

Real in value: 66.59 6.05 7.61

Mark in NMR, deuterochloroform solvent, the TMS.

7.33（1H，s，

）;7.36（5H，s，

）;

7.30（5H，s，

）;7.06（3H， ）;

6.94（1H，d，-NH-C-）;5.90（1H，d，-NH-CO ₂-）;

5.11（2H，s，

）;5.0（2H，s， ）;

4.61（2H，m，

）;3.18，2.80（1H，1H，q，q， ）;

2.16（6H，s，

）;1.5（3H，d，-CH ₃）;

Above-mentioned gained β-benzyl N-CBZ-L-α-aspartyl D-alanyl-2,6-xylidene(s) acid amides 3.12 grams (6 millimole), in 200 ml methanol and 50 ml waters (suspension), add 0.4 gram palladium black, room temperature normal pressure hydrogenation 6 hours gets a clear solution, the elimination palladium black, removal of solvent under reduced pressure gets white solid, uses ethanol: water (6:4) recrystallization gets 1.04 gram (60%) products.M.p.232-234 ℃, [α] ³¹ _D+ 63 ° of (C=1, H ₂O) sugariness 500X sucrose.For practicality, we have also prepared the mix product of the corresponding diastereomer of L-Ala raceme, sugariness about 250 times to sucrose.

Ultimate analysis: C ₁₅H ₂₁N ₃O ₄2H ₂O/3

Theoretical value: C, 56.43, H, 6.58, N, 13.17

Experimental value: 56.16,6.94,13.16

NMR(heavy water solvent)

7.2（3H，s，

），4.7（2H，d，-CH ₂-）;

3.82（1H，m，CH）;2.83（1H，q， ）;

2.2（6H，s， ）;1.6（3H，d，-CH ₃）.

Claims (14)

1, a class L-aspartyl dipeptide sweetener is characterized in that this compounds general expression is:

R in the formula ₂Be respectively CH ₂, H, CH ₂OH;

R ₂Be respectively

2, L-aspartyl dipeptide sweetener preparation method according to claim 1 is characterized in that adopting following method synthetic:

A) amino acid is through carbobenzoxy chloride; contraposition has carbobenzoxy chloride, acids, the formyl halide protection ammonia terminal amino acid of replacement; alcohols, trimethylchlorosilane protection carboxylic terminal amino acid; the esterification of carboxylic terminal amino acid elder generation, amidation then connect peptide, the then amino HCl, Phenylsulfonic acid of using; carboxylic acid halides; protections such as carbobenzoxy are sloughed again, connect peptide then.

B) amino acid of two kinds of protections through dicyclohexylcarbodiimide, mix after the acid anhydrides condensation get dipeptide compound.

C) peptide compounds that contains protecting group is sloughed protecting group through palladium black hydrogenation, Hydrogen bromide.

3, it is characterized by amino acid according to the described synthetic method of claim 2 is D-or D, L-L-Ala, D-or D, L-Serine, glycine, L-Aspartic Acid.

4, it is characterized in that according to the described synthetic method of claim 2 protection of ammonia terminal amino acid is carbobenzoxy chloride, organic acid, mineral acid, also available formyl halide.

5, it is characterized in that according to the described synthetic method of claim 4 solvent of ammonia terminal amino acid protection is anhydrous diethyl ether, water, formic acid, tetrahydrofuran (THF), methylene dichloride, chloroform, ethyl acetate.

6, synthetic method according to claim 2 is characterized in that carboxylic terminal amino acid protecting group is fenchol, iso-butylene, Acibenzolar, transesterify.

7, synthetic method according to claim 6 is characterized in that carboxylic terminal amino acid and protecting group reaction solvent are benzene, toluene, the second wine made of broomcorn millet, vinyl acetic monomer, tetrahydrofuran (THF), dimethyl formamide, ethanol, chloroform, methylene dichloride, dioxane.

8, synthetic method according to claim 7 is characterized in that the ore deposit acid of carboxylic terminal amino acid carboxyl esterification, Phenylsulfonic acid, Catalyzed by p-Toluenesulfonic Acid.

9, synthetic method according to claim 2 is characterized in that the amino acid condensation agent of two kinds of protections is dicyclohexylcarbodiimide, isobutyl chlorocarbonate, triethylamine, N-methylmorpholine.

10, synthetic method according to claim 9 is characterized in that the condensation reaction solvent is chloroform, methylene dichloride, vinyl acetic monomer.

11, synthetic method according to claim 10 is characterized in that setting-up point is-15 to 15 ℃.

12, synthetic method according to claim 2 is characterized in that the deprotection base, by palladium carbon catalysis hydrogen Jie, hydrogen bromide hydrolysis.

13, synthetic method according to claim 12 is characterized in that catalytic hydrogenolysis, and solvent is water, methyl alcohol, dioxane, tetrahydrofuran (THF), acetic acid, Virahol, propyl carbinol.

14, the sweet prod that obtains according to claim 1-13 both can be the simple substance product, also can be L-Asp-D, L-Ala-OR and L-Asp-D, the mixture of L-Ser-OR diastereomer.